Photoelectric vehicle identification system



June 6, 1967 J. GOLDBERG 3,324,301

PHOTOELECTRIC VEHICLE IDENTIFICATION SYSTEM Filed Feb. 28, 1963 FlG.2

JACOB GOLDBERG INVENTOR.

ATTORNEYS United States Patent Ofi ice 3,324,301 Patented June 6, 1967PHOTOELECTRIC The present invention relates to radiant-energyidentification systems and methods and, more particularly, to systemsand apparatus in which radiant energy, such as electromagnetic Waves(light, infrared, microwave, etc.) or other types of radiant energy, allhereinafter embraced by the term radiation, is employed to scan a codedidentification tag or member.

One of the important uses for such systems is in the identification ofmoving vehicles, such as railroad cars or the like; and numerous typesof reflecting surfaces having different radiation-absorbing regions,including slots, have been proposed. In these prior proposals however,the coating of dirt, grease, ice and other contaminants upon absorbingand/or reflecting regions have rendered the systems less thansatisfactory in reliability and performance, in actual practice.

An object of the present invention, accordingly, is to provide a new andimproved system and method that shall not be subject to suchdisadvantages; but that, to the contrary, shall provide reliable signalreflection and scanning of coded reflecting surfaces, irrespective ofsignificant variations in the surfaces caused by contamination and othercauses.

A further object is to provide a novel identification tag or memberparticularly adapted for use in the system of the invention.

Other and further objects will be explained hereinafter and will be moreparticularly pointed out in connection with the appended claims; theinvention being described in connection with the accompanying drawing:

FIG. 1 of which is a combined perspective and blockdiagram view of apreferred embodiment;

FIG. 2 is a fragmentary isometric view of a modification employingilluminated and shadow regions of an identification tag or member; and

FIG. 3 is a side elevation of still another modification.

Referring to FIG. 1, a source of radiation, as above defined, such as,for example, an infrared or visible light source 9, energized from acircuit 13, as of direct-current, alternating-current or stroboscopictype, is shown provided with relatively directional beam-forming orprojecting means, illustrated as a parabolic reflector 11, to transmit aconfined radiation beam T long a path toward an identification tage ormember I, carried by, for example, a vehicle, such as a railroad-carundercarriage or frame 7.

In accordance with the invention, and as distinguished from prior-artproposals, the transmitted or incident radiation beam T need notdirectly impinge upon and reflect from the coded indentification surface1 of the tage or member I; but, in FIG. 1, is shown, rather, impingingat P upon a reflecting surface 5 disposed rearward of the identificationsurface 1 and defining or enclosing an angle a therebetween. The beam Tis reflected from the surface 5 at P along the path R. This reflectiongenerally is diffused or scattered, but specular reflection, if desired,may be attainedall such being herein referred to generically asreflection or reflecting.

The reflected radiation R is permitted to pass through identificationcode apertures, such as parallel spaced pluralities of slots 3, invarious code arrangements, in the otherwise radiation-opaqueidentification surface 1, as the vehicle moves in the direction of thearrow transversely past the source 9 along a predetermined course; thusproviding coded on-otf signals at a preferably directional receiver 15,for indicating, storing or otherwise processing at the data apparatus17, of any desired conventional type.

It has been found that .this background illumination technique, whereinthe incident radiation is not directly reflected from the coded surfaceitself (which, to the contrary, is disposed in the path T-R betweentransmitter or source and receiver so that the received radiation, whilepassing through the coded surface, has been reflected from an adjacentreflecting surface before being received), renders the systemsubstantially insensitive to normally encountered contamination. Whereasprior-art reflecting tags must rely upon the contrast between directlyreflecting or absorbing regions and thus, as before stated, aredetrimentally affected by coatings of ice, mud and other contaminants,the method of the present invention provides a reliable on-ofl signalirrespective of contamination upon the surfaces 1 or 5, provided onlythat the slots 3 are not completely closed.

In experimental tests, for example, employing a General Electric typeincandescent projection lamp 9 of the BMA ISO-watt type, positionedabout three feet from the tag I, and a receiver 15-17 employing a TexasInstrument Company 1N2175 photodiode and receiving circuit positionedabout four feet from the tag I, on-off signal contrast in the ratio ofover lOO-to-l was obtained between the signal in the presence of a slot3 and the nosignal condition. The slots 3 were about three inches longand a half-inch wide, with each surface 1 and 5 being about four incheswide. For inexpensive construction purposes, indeed, the surfaces 1 and5 were formed as an angle iron with substantially a ninety-degreeincluded angle a between the connected surfaces 1 and 5. Even when thesurface 5 was painted black to constitute the worst conditions ofcontamination thereof, on-off signal ratios in excess of 4-to-1 werereliably received.

In FIG. 3, a modified construction of U-shaped form is illustrated, inwhich the identification surface 1", slotted at 3", is mounted by aconnecting surface 2 substantially parallel to, but spaced forward of,the reflecting surface 5".

It is not necessary, moreover, that the radiation pass through the slotsof the identification surface after reflection from the reflectingsurface of the tag, as in FIGS. 1 and 3. Thus, in FIG. 2, the radiationT from the source first passes through the slots 3', cut in from theouter edge of the identification surface 1, located on the transmitterside of the reflecting surface 5', and then reflects at P from thereflecting surface 5' toward the receiver. A coded shadow distribution,corresponding to the presence and absence of slots 3, is thus formedupon the reflecting surface 5, as indicated by the shaded and unshadedregions, returning appropriate on-oif signals along the reflectedbeam-path R to the receiver.

Clearly, as previously intimated, other types of radiation, includingmicrowaves, and other configurations of apertures, slots, etc., may beemployed by those skilled in the art; all such being considered to fallwithin the spirit and scope of the invention as defined in the appendedclaims.

What is claimed is:

1. An identification system for vehicles and the like which move along apredetermined course, comprising a radiation transmitter and a radiationreceiver located at one side of said course, each of said vehicleshaving an identification member fixed thereto and exposed to theradiation from said transmitter, each of said members having anidentification surface opaque to said radiation but provided with aseries of code apertures arranged in sequence along said course andhaving a radiation-reflecting surface fixed near the identificationsurface and oriented to reflect radiation from said transmitter to saidreceiver, said apertures being positioned in the path of said radiationreceived at said receiver by reflection from said reflecting surface assaid vehicles move along said course past said transmitter and saidreceiver.

2. The system of claim 1, said apertures being positioned to pass theradiation from said transmitter before reflection from said reflectingsurface.

3. The system of claim 1, said apertures being positioned to pass theradiation from said transmitter after reflection from said reflectingsurface.

4. The system of claim 1, said apertures being parallel slots.

5. The system of claim 4, said slots being cut in from an edge of saididentification surface.

6. The system of claim 1, said identification surface and saidradiation-reflecting surface being disposed at an angle to one anotherless than 180 degrees.

7. The system of claim 6, said angle being substantially 90 degrees.

8. The system of claim 1, said identification surface and saidreflecting surface being substantially parallel.

References Cited UNITED STATES PATENTS 1,811,595 6/1931 Powers 88-75 X1,832,196 11/1931 Ferguson 88-75 X 1,962,467 6/1934 Sholkin 25.0-219 X2,287,965 6/1942 Borberg 250-219 X 2,482,242 9/1949 Brustman 250-2192,581,552 1/1952 OHagan et al. 2462 2,612,994 10/ 1952 Woodland et al.250-223 X 2,769,922 11/1956 Peery 250-219 2,944,156 7/1960 Davy et al250-219 3,041,462 6/1962 Ogle 250-239 X 3,145,291 8/1964 Brainerd250-219 X WALTER STOLWEIN, Primary Examiner.

2O RALPH G. NILSON, Examiner.

M. A. LEAVITT, Assistant Examiner.

1. AN IDENTIFICATION SYSTEM FOR VEHICLES AND THE LIKE WHICH MOVE ALONG APREDETERMINED COURSE, COMPRISING A RADIATION TRANSMITTER AND A RADIATIONRECEIVER LOCATED AT ONE SIDE OF SAID COURSE, EACH OF SAID VEHICLESHAVING AN IDENTIFICATION MEMBER FIXED THERETO AND EXPOSED TO THERADIATION FROM SAID TRANSMITTER, EACH OF SAID MEMBERS HAVING ANIDENTIFICATION SURFACE OPAQUE TO SAID RADIATION BUT PROVIDED WITH ASERIES OF CODE APERTURES ARRANGED IN SEQUENCE ALONG SAID COURSE ANDHAVING A RADIATION-REFLECTING SURFACE FIXED NEAR THE IDENTIFICATIONSURFACE AND